The present invention relates to a fluid filtering apparatus adapted for removal of various noxious gases such as chlorine gas and ammonium gas or noxious ions present in the air; ions, moisture or molecular impurities present in non-aqueous liquids such as lubricating oil, machining oil, cleaning oil and organic solvents; and oily contents, ions or molecular impurities present in aqueous liquids such as potable water, waste water, lubricating liquid, working water and cleaning liquid, and more particularly to such fluid filtering apparatus utilizing adsorbent.
In the conventional adsorptive fluid filtering apparatuses utilizing adsorbent, the fluid to be treated passes through the apparatus merely in contact with the adsorbent or passes first through an electric field so that any impurities contained therein are charged and then passes in contact with the adsorbent. Such adsorptive filtering apparatuses of prior art have been unsatisfactory in their adsorption capacities and also because of the limited saturated adsorption levels of used adsorbents, since these well known apparatuses exclusively rely upon a relatively low inherent adsorption potential of the adsorbent on its effective hole surface as an adsorption power. Additionally, after saturation, the adsorbent can not be reused and must be thrown away. This disadvantageously increases the operation cost and requires a large-sized waste disposal equipment.
The present invention is based on a surprising revelation that the adsorption of impurities or the like onto the adsorbent is caused not by physical capillarity, as would be expected based on established theory, but really by a mutual attraction, under effect of a Coulomb's force, between electric charges carried by the adsorbent surface and those carried by impurities or ions.